Canopies such as those above fuel dispensing pumps at service stations are typically formed of a horizontal framework supporting a roof and supported in turn above a raised concrete island by a plurality of hollow vertical steel columns. The roof of the canopy is flat. Typically, rain falling on the roof of the canopy drains through these hollow support columns. The lower end of each support column is embedded in concrete and includes an opening near or at its base for draining the accumulated rainwater. The water may be drained from the column either laterally through a hole in the column base, at the concrete level, down to a drainage pipe leading to an opening in the side of the concrete island, or into an underground drainage conduit that directs the water into a sewer or drainage field. These three drainage systems for the support columns are susceptible to becoming partially or completely clogged with leaves and other wind borne debris over time, thereby causing the column to retain water. Standing water in the column promotes rust and corrosion on its interior surface and results in structural deterioration. If the column becomes sufficiently weakened, the canopy will collapse. The typical repair method involves replacing the entire canopy and its supports or temporarily removing just the canopy, replacing the columns and then re-installing the canopy on the new columns. Both of these methods are expensive and time-consuming, requiring the site to be closed for several days during the repair. Therefore, a need exists for an efficient, low cost system for replacing rust-weakened canopy support columns.